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Ford F-250 & Ford F-350The heavier duty full sized trucks from Ford, offering bigger, more powerful engines and drivetrains for the abuse they may go through in the workplace.
Hello y'all,
Im new here could use some help. I have a 88 f 250 5.8l 4x4. Chasing a issue with the ecm. A prior owner installed a hypertechoff the back of the ecm. There is a short in the harness on the hypertech. So if you slightly touch the harness it kills the power to the fuel pump. I called hypertech and they said to remove it and it will be good. Well when i remove the chip i get no power to the fuel pump, so i figured it needed a ecm ordered the correct one and installed it and same problem. So i pulled it back out put the old one back in with the hypertech
and taped the harness down and it runs. But i really want it fixed correctly. Any help would be great
Thanks
Id be suspect of the OE harness/connector since the issue can be created during a wiggle test..
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thanks for the reply. Ive triple checked the harness, it has something to do with the hypertech connection to the ecm. Ive narrowed it down to that silver ribbon harness in the pic. But the damn thing will not work with out it.
I thought you meant you installed the OE connector to ECM and it still failed. So we’re clear,, both ECMs loose fuel pump control without the hyper installed?
Actually back then Ford called the module EEC..
The timed/fuel pump run is a ‘ground’ supplied to fuel pump relay coil (in the engine comp box) by the EEC to close the relays contacts for power distribution on out and through the inertia to the pump..
I believe the ground control out of the EEC connector was on pin 22. Might be on your diagrams there as well?
You might back probe the connector with the hyper removed to see if it’s supplying a ground with KOEO,, but it will only be available for a few seconds. You can also run the pump continuous for testing with a bridged connection at the VIP test connector.
In an emergency, or stranded, you can add the needed ground for pump run, but you loose the ‘safety’ of pump canceling on a stall during an accident etc. I’d discourage any operating bypass, but mentionable...
I used to frequent a local lake that didnt have fuel available. We would bring cans and such, but I had a made up fuel tap that I’d attach to the fuel rail, grounding the EEC test connector (KOEO, KOER) and had all the fuel available for the entire vacation to fill cans.. Or, until the truck ran out
Last edited by Hayapower; Feb 25, 2019 at 09:09 AM.
Ecm hypertechissues
